@Beta @GwtCompatible public abstract class AbstractCache<K,V> extends Object implements Cache<K,V>
Cache
interface to minimize the
effort required to implement this interface.
To implement a cache, the programmer needs only to extend this class and provide an
implementation for the Cache.getIfPresent(K)
method. getAllPresent(java.lang.Iterable<? extends K>)
is implemented in
terms of getIfPresent
; invalidateAll(Iterable)
is implemented in terms of
invalidate(java.lang.Object)
. The method cleanUp()
is a no-op. All other methods throw an
UnsupportedOperationException
.
Modifier and Type | Class and Description |
---|---|
static class |
AbstractCache.SimpleStatsCounter
A thread-safe
AbstractCache.StatsCounter implementation for use by Cache implementors. |
static interface |
AbstractCache.StatsCounter
Accumulates statistics during the operation of a
Cache for presentation by Cache.stats() . |
Modifier | Constructor and Description |
---|---|
protected |
AbstractCache()
Constructor for use by subclasses.
|
Modifier and Type | Method and Description |
---|---|
V |
apply(K key)
Deprecated.
|
ConcurrentMap<K,V> |
asMap()
Returns a view of the entries stored in this cache as a thread-safe map.
|
void |
cleanUp()
Performs any pending maintenance operations needed by the cache.
|
V |
get(K key,
Callable<? extends V> valueLoader)
Returns the value associated with
key in this cache, obtaining that value from
valueLoader if necessary. |
ImmutableMap<K,V> |
getAllPresent(Iterable<? extends K> keys)
Returns a map of the values associated with
keys in this cache. |
V |
getUnchecked(K key)
Deprecated.
|
void |
invalidate(Object key)
Discards any cached value for key
key . |
void |
invalidateAll()
Discards all entries in the cache.
|
void |
invalidateAll(Iterable<?> keys)
Discards any cached values for keys
keys . |
void |
put(K key,
V value)
Associates
value with key in this cache. |
long |
size()
Returns the approximate number of entries in this cache.
|
CacheStats |
stats()
Returns a current snapshot of this cache's cumulative statistics.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
get, getIfPresent
public V get(K key, Callable<? extends V> valueLoader) throws ExecutionException
Cache
key
in this cache, obtaining that value from
valueLoader
if necessary. No observable state associated with this cache is modified
until loading completes. This method provides a simple substitute for the conventional
"if cached, return; otherwise create, cache and return" pattern.
Warning: as with CacheLoader.load(K)
, valueLoader
must not return
null
; it may either return a non-null value or throw an exception.
get
in interface Cache<K,V>
ExecutionException
- if a checked exception was thrown while loading the valuepublic ImmutableMap<K,V> getAllPresent(Iterable<? extends K> keys)
Cache
keys
in this cache. The returned map will
only contain entries which are already present in the cache.getAllPresent
in interface Cache<K,V>
public void put(K key, V value)
Cache
value
with key
in this cache. If the cache previously contained a
value associated with key
, the old value is replaced by value
.
Prefer Cache.get(Object, Callable)
when using the conventional "if cached, return;
otherwise create, cache and return" pattern.
public void cleanUp()
Cache
public long size()
Cache
public void invalidate(Object key)
Cache
key
.invalidate
in interface Cache<K,V>
public void invalidateAll(Iterable<?> keys)
Cache
keys
.invalidateAll
in interface Cache<K,V>
public void invalidateAll()
Cache
invalidateAll
in interface Cache<K,V>
public CacheStats stats()
Cache
public ConcurrentMap<K,V> asMap()
Cache
@Deprecated public V getUnchecked(K key)
Cache
key
in this cache, first loading that value if
necessary. No observable state associated with this cache is modified until computation
completes. Unlike Cache.get(K, java.util.concurrent.Callable<? extends V>)
, this method does not throw a checked exception, and thus should
only be used in situations where checked exceptions are not thrown by the cache loader.
Warning: this method silently converts checked exceptions to unchecked exceptions, and should not be used with cache loaders which throw checked exceptions.
getUnchecked
in interface Cache<K,V>
@Deprecated public V apply(K key)
Cache
Function
interface; use Cache.get(K, java.util.concurrent.Callable<? extends V>)
or
Cache.getUnchecked(K)
instead.Copyright © 2010-2012. All Rights Reserved.